-find_package(MPI REQUIRED)
-set(CMAKE_CXX_COMPILE_FLAGS ${CMAKE_CXX_COMPILE_FLAGS} ${MPI_COMPILE_FLAGS})
-set(CMAKE_CXX_LINK_FLAGS ${CMAKE_CXX_LINK_FLAGS} ${MPI_LINK_FLAGS})
-include_directories(${MPI_INCLUDE_PATH})
+if(NOT DEFINED ENV{MPI_DISABLED})
+  find_package(MPI REQUIRED)
+  set(CMAKE_CXX_COMPILE_FLAGS ${CMAKE_CXX_COMPILE_FLAGS} ${MPI_COMPILE_FLAGS})
+  set(CMAKE_CXX_LINK_FLAGS ${CMAKE_CXX_LINK_FLAGS} ${MPI_LINK_FLAGS})
+  include_directories(${MPI_INCLUDE_PATH})
+else()
+  message("O815: MPI support is disabled!")
+endif()